Fuel supply systems for internal combustion engines

ABSTRACT

A fuel supply system for an internal combustion engine comprises a pump feeding fuel to one or more injector nozzles. A digital electronic fuel control unit controls the flow of fuel to the nozzles in response to signals from a digital encoder whose output is dependent upon the angle of a vane controlling the admission of combustion air into the engine. The digital encoder includes an arm mounted on a spindle carrying the vane. The arm has a series of contacts thereon which move relative to fixed contact areas as the vane pivots with the spindle so that a digital output is obtained in accordance with the angle of the vane.

United States Patent Hughes Oct. 14, 1975 FUEL SUPPLY SYSTEMS FORINTERNAL 3,720,193 3/1973 Monpetit 123/32 EA COMBUSTION ENGINES3,752,139 8/1973 Asplund 123/117 R 3,780,711 12/1973 Lindberg 123/32 EA[75] Inventor: Ronald W1lliam Hughes,

Birmingham, England OTHER PUBLICATIONS 73 Assignee; The Lucas ElectricalCompany Electronic Fuel Injection Reduces Automotive Pollu- Limited,Birmingham, England tion, M. Williams, Electronics, Sept. 11, 1972, pp.

121-125. [22] Filed: May 1, 1973 [21] Appl. No.2 356,128 PrimaryExaminer-Charles J. Myhre Assistant Examiner-Joseph Cangelosi ForeignApplication Priority Data Attorney, Agent, or Firm-Holman & Stern May13, 1972 United Kingdom 22781/72 [57] ABSTRACT [52] 123/32 EA; 123/32AE; 123/117 R; A fuel supply system for an internal combustion en- 2123/1 19 R; 123/139 E gine comprises a pump feeding fuel to one or morein- [51] Int. Cl. F021) 5/02 jector noZz]S A digital electronic fuelcontrol unit [58] held of Search 123/32 32 139 controls the flow of fuelto the nozzles in response to 123/119 signals from a digital encoderwhose output is dependent upon the angle of a vane controlling theadmis- [56] References C'ted sion of combustion air into the engine. Thedigital en- UNITED STATES PATENTS coder includes an arm mounted on aspindle carrying 3,592,178 7/1971 Schiff 123/148 1-: the vane The armhas a Series Of Contacts thereon 3,593,692 7/1971 Scholl 123/32 EA whichmove relative to fixed contact areas as the vane 3,612,008 10/1971Beishirw 123/32 EA pivots with the spindle so that a digital output isob- 3,616,780 1 1 H8 6 123/32 EA tained in accordance with the angle ofthe vane. 3,669,081 6/1972 Mon Petit 1. 123/139 E 3,689,753 9/1972 Lucas123/32 EA 6 Claims, 4 Drawing Figures 1 /l 1 9 DIGITAL DIGITAL FUELCONTROLLER u THROTTLE 16 B/ AIR INTAKE MANIFOLD VALVE I PU P ENGINE I!I7 TI HER SPEED SENSOR A '8 US. Patent Oct.14,1975 Sheet 1 of2 3,911,872I IO q' DIGITAL DIGITAL FUEL CONTROLLER |5 IZflL 2 k2 I2 U L] u u 13/AIR INTAKE MANIFOLD SKEJE H H H ENGINE vg fi /ZQ DIGITAL DIGITAL CONTROLENCODER AS 5 SPRAY NOZZLE TIIIRAOLTVTELE I6 I I II II I II UT ENGINE Z iSSPEED PUMP ZZ L F G I SP QE IE T OR I U.S. Patent Oct. 14, 1975 Sheet 2of2 3,911,872

FUEL SUPPLY SYSTEMS FOR INTERNAL COMBUSTION ENGINES This inventionrelates to fuel supply systems for internal combustion engines.

A fuel supply system in accordance with the invention includes athrottle valve for controlling the admission of combustion air to anengine and having an angularly movable spindle, a digital encoder forsaid throttle valve for producing a digital output corresponding to theangular position of the spindle, and a digital electronic fuel controlunit responsive to the output of the digital encoder for controlling therate at which fuel is supplied to the engine in accordance with theoutput of the digital encoder.

In the accompanying drawings FIGS. 1 and 2 are diagrammaticrepresentations of two examples of fuel supply systems in accordancewith the invention, for an internal combustion engine, and

FIGS. 3 and 4 are mutually perpendicular sections through a throttlevalve which can be employed in either system.

The system shown in FIG. 1 includes a digital electronic fuel controldevice which controls the supply of fuel, pressurised by a pump 11, toinjection nozzles 12 in an air intake manifold 13 of the engine. Thedigital control device 10 has inputs from a speed sensing device 14 andfrom a digital encoder 15 associated with a throttle 16 which controlsadmission of combustion air to the manifold 13 under the control of apedal 17. The timing of the injections is controlled by a timing device18. The quantity injected in each cycle is controlled by the device 10.

In the system shown in FIG. 2, a single spray nozzle 19 is used whichsprays fuel into air intake downstream of the throttle. In this case,digital control device 20 is used to drive a variable speed electricmotor 21 which drives a pump 22 supplying the nozzle 19. The rate ofinjection is controlled by the device 20.

In each case, the throttle valve 16 has a spindle 23 which is turned tomove a vane 24 within a passage through the throttle valve body. Anelectrically insulating arm 25 is mounted on the spindle 23 and a row ofcontacts 26 on this arm 25 engage a printed circuit board 27 mounted onthe body. One of these contacts is permanently in contact with anarcuate conductive area 27a on this board. The remaining contacts 26 runover arcuate rows of alternately conductive and nonconductive areas onthe board 27, the conductive areas of each arcuate row being connectedtogether and thereby to an associated one of a plurality of terminals27b on the board. Thus, for any position of the spindle a predeterminednumber of the terminals 27b are connected to the area 27a and theremainder are isolated from the area 27a. Preferably the conductiveareas on the board are arranged to give a Gray, coded digital output, asis already known in shaft encoders, so that only one output changes atany time as the spindle is turned.

The encoder 15 provides a digital input into the digital control device10 or 20, which, taken in combination with the signal from the speedsensing device 14 determines the output of the device 10 to control therate of fuel input.

Details concerning the digital fuel control circuits l0 and 20, speedcenters 14, and timing device 18 may be found, for example, in US. Pat.No. 3,689,753, issued Sept. 5, 1972, to Williams et al and assigned tothe same assignee as the present application, said patent beingexpressly incorporated herein by reference.

I claim:

1. A fuel supply system including a throttle valve for controlling theadmissions of combustion air to an engine and having an angularlymovable spindle, a digital encoder for said throttle valve for producinga digital output signal corresponding to the angular position of thespindle, and a digital electronic fuel control unit responsive to saidoutput signal of the digital encoder for controlling the rate at whichfuel is supplied to an engine in accordance with said output signal ofthe digital encoder, said encoder including an arm mounted for angularmovement with the spindle, a plurality of contacts mounted on said arm,the number of said contacts corresponding to the number of bits of saiddigital output signal, and a plurality of fixed digitally coded contactpaths equal in number to and arranged in a one-to-one contactingrelationship with said contacts on said arm and relative to which thecontacts on the arm are movable upon angular movement of the spindle soas to generate a plurality of different digitally coded output signals.

2. A fuel supply system as claimed in claim 1, including at least onefuel injector nozzle for supplying fuel to the engine, and wherein thefuel control unit is arranged to control the flow of fuel to the said atleast one nozzle.

3. A fuel supply system as claimed in claim 2, wherein a pump isarranged to supply fuel to the control unit which controls flow of fueltherefrom to the said at least one nozzle.

4. A fuel supply system as claimed in claim 2, wherein a pump isprovided for supplying fuel, and a variable speed motor controlled bythe fuel control unit drives the pump.

5. A fuel supply system as claimed in claim 1, wherein one of thecontacts on the arm is permanently in contact with an arcuate conductivearea and other contacts on the arm are movable over arcuate rows ofalternately conductive and non-conductive areas, the conductive areas ofeach arcuate row being connected to a terminal so that for any positionof the spindle a predetermined number of the terminals are connected tothe said arcuate conductive area and the remainder are isolated from thesaid arcuate conductive area.

6. A fuel supply system as claimed in claim 5, wherein the conductiveareas are arranged so that only one output changes at any time as thespindle is turned. i

1. A fuel supply system including a throttle valve for controlling theadmissions of combustion air to an engine and having an angularlymovable spindle, a digital encoder for said throttle valve for producinga digital output signal corresponding to the angular position of thespindle, and a digital electronic fuel control unit responsive to saidoutput signal of the digital encoder for controlling the rate at whichfuel is supplied to an engine in accordance with said output signal ofthe digital encoder, said encoder including an arm mounted for angularmovement with the spindle, a plurality of contacts mounted on said arm,the number of said contacts corresponding to the number of bits of saiddigital output signal, and a plurality of fixed digitally coded contactpaths equal in number to and arranged in a one-to-one contactingrelationship with said contacts on said arm and relative to which thecontacts on the arm are movable upon angular movement of the spindle soas to generate a plurality of different digitally coded output signals.2. A fuel supply system as claimed in claim 1, including at least onefuel injector nozzle for supplying fuel to the engine, and wherein thefuel control unit is arranged to control the flow of fuel to the said atleast one nozzle.
 3. A fuel supply system as claimed in claim 2, whereina pump is arranged to supply fuel to the control unit which controlsflow of fuel therefrom to the said at least one nozzle.
 4. A fuel supplysystem as claimed in claim 2, wherein a pump is provided for supplyingfuel, and a variable speed motor controlled by the fuel control unitdrives the pump.
 5. A fuel supply system as claimed in claim 1, whereinone of the contacts on the arm is permanently in contact with an arcuateconductive area and other contacts on the arm are movable over arcuaterows of alternately conductive and non-conductive areas, the conductiveareas of each arcuate row being connected to a terminal so that for anyposition of the spindle a predetermined number of the terminals areconnected to the said arcuate conductive area and the remainder areisolated from the said arcuate conductive area.
 6. A fuel supply systemas claimed in claim 5, wherein the conductive areas are arranged so thatonly one output changes at any time as the spindle is turned.